Related Experiment Video
Updated: Jul 6, 2026
Single-cell Microfluidic Analysis of Bacillus subtilis
Published on: January 26, 2018
Bacitracin sensing in Bacillus subtilis
Eva Rietkötter1, Diana Hoyer, Thorsten Mascher
1Department of General Microbiology, Georg-August-University, Göttingen, Germany.
Abstract:
The extracellular presence of antibiotics is a common threat in microbial life. Their sensitive detection and subsequent induction of appropriate resistance mechanisms is therefore a prerequisite for survival. The bacitracin stress response network of Bacillus subtilis consists of four signal-transducing systems, the two-component systems (TCS) BceRS, YvcPQ and LiaRS, and the extracytoplasmic function (ECF) sigma factor sigma(M). Here, we investigated the mechanism of bacitracin perception and the response hierarchy within this network. The BceRS-BceAB TCS/ABC transporter module is the most sensitive and efficient bacitracin resistance determinant. The ABC transporter BceAB not only acts as a bacitracin detoxification pump, but is also crucial for bacitracin sensing, indicative of a novel mechanism of stimulus perception, conserved in Firmicutes bacteria. The Bce system seems to respond to bacitracin directly (drug sensing), whereas the LiaRS TCS and sigma(M) respond only at higher concentrations and indirectly to bacitracin action (damage sensing). The YvcPQ-YvcRS system is subject to cross-activation via the paralogous Bce system, and is therefore only indirectly induced by bacitracin. The bacitracin stress response network is optimized to respond to antibiotic gradients in a way that maximizes the gain and minimizes the costs of this stress response.
Insights
Bacillus subtilis survival depends on detecting antibiotics like bacitracin. The BceRS-BceAB system directly senses bacitracin, initiating a tiered resistance response for optimal microbial defense.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Stress Response
Background:
- Antibiotic presence poses a significant threat to microbial survival.
- Effective detection of antibiotics and induction of resistance mechanisms are crucial for microbial life.
- Bacillus subtilis employs a complex network of four signal-transducing systems for bacitracin stress response.
Purpose of the Study:
- To investigate the mechanism of bacitracin perception in Bacillus subtilis.
- To elucidate the response hierarchy within the bacitracin stress response network.
- To understand how Bacillus subtilis optimizes its response to antibiotic gradients.
Main Methods:
- Analysis of the BceRS-BceAB two-component system (TCS) and ABC transporter.
- Investigating the roles of LiaRS TCS and sigma(M) in bacitracin response.
- Examining the YvcPQ-YvcRS system's interaction with the Bce system.
Main Results:
- The BceRS-BceAB module is the primary and most sensitive determinant of bacitracin resistance.
- BceAB functions as both a bacitracin detoxification pump and a crucial sensing component, indicating a novel direct drug sensing mechanism.
- LiaRS TCS and sigma(M) respond indirectly to bacitracin at higher concentrations, while YvcPQ-YvcRS is cross-activated by the Bce system.
Conclusions:
- The Bce system directly senses bacitracin, initiating a hierarchical stress response.
- Bacillus subtilis utilizes a sophisticated network for efficient and cost-effective antibiotic resistance.
- The identified sensing mechanism is conserved in Firmicutes bacteria, highlighting its evolutionary significance.
